Currently, many mobile terminal manufacturers cooperate with mobile operators to develop appropriate customized mobile terminals for operators, and the operators gain market shares by presenting mobile terminals as gifts. This requires that the customized mobile terminals have network locking function, and ensures the users of the customized mobile terminals can only use the services provided by the operator. Afterwards, the operator returns a portion of the acquired profits back to the mobile terminal manufacturers to ensure that the interests of the mobile terminal manufacturers. It can be seen that, in the process of achieving the interests of both parties, the network locking mechanism is an important step, and its security is essential, only if the network locking information remains in effect, can the interests of the operators and the manufacturers be guaranteed.
However, many hackers, in order to reap illegal profits, study the security vulnerabilities existing in the current network locking mechanisms and use these vulnerabilities to crack the network locking mechanism, the cracked and customized mobile terminal can use services provided by other operators. These hackers are paid to illegally crack the customized mobile terminals for the users in order to seek their own interests, and this seriously damages the legitimate rights and interests of the operators and the mobile device manufacturers.
In order to maintain the legitimate rights and interests of the operators and the mobile terminal manufacturers, it not only needs to obtain protection from the legal aspects, but also needs to upgrade the network locking technology to enhance the product competitiveness and user satisfaction of the mobile terminals. The existing network locking method is typically as follows: pre-store the encrypted subscriber identity module (SIM) card information, such as mobile country code (MCC) and Mobile Network Code (MNC), in the mobile terminal; when the mobile terminal is powered on each time, verify the MCC and MNC in the SIM card, namely, compare the stored MCC and MNC with the MCC and MNC in the SIM card inserted in the mobile terminal, if there is a verification error, the mobile terminal cannot work properly, so as to achieve the network locking function of the mobile terminal. It can be seen that, the existing network locking method only designs the network locking scheme at the side of the mobile terminal, that is, the existing solution only optimizes the design of the software or hardware of the mobile terminal, so as to improve the security of the network locking mechanism. However, the mobile terminal can only verify whether the SIM card is a customized SIM card or not, while the SIM card cannot judge whether the mobile terminal in which the SIM card is inserted is a customized mobile terminal or not, that is, they can not verify each other, so that the customized SIM card can also be used even if it is inserted into a non-customized mobile terminal, thus deteriorating legitimate rights and interests of the operators and the mobile terminal manufacturers.